Brake



April 19, 1938. L. BERTRAND 9 5 BRAKE 'F'ild Jan. 12, 1957 s Sheets-Sheet 1 INVENTOR= LUCIEN BERTRAND ATTORNEYS Aprll 19, 1938. L. BERTRAND 2,114,672

BRAKE Filed Jan 12, 1937 3 Sheets-Sheet 2 i INVENTOR= LUCIEN BERTRAND lawo ag ATTORN [1Y5 April 1933- L. BERTRAND 2,114,672

\ BRAKE Filed Jan. 12, 1937 5 Sheets-Sheet s INVENTOR= LUCIEN BERTRAND BWYVZ:

ATTRNEX5 Patented Apr. 19, 1938 UNKTED STATE BRAKE Lucien Bertrand, Paris, France, assignor to Sccit Anonyme Fr'anearse (in Fer-ode, Pans,

France Application January 12, 1937. Serial No. 120,162 In France February 8, 1936 3 Claims.

The present invention relates to a brake more particularly intended for motor vehicles of small power and so arranged as to combine various essential qualities one or more of which are lacking in brakes actually in use, viz: lightness, simplicity, low cost price, great ease of adjustment, progressivity of the braking action, and nonexcessive but regular power.

According to the present invention it is possible to obtain at the same time these various qualities by judiciously combining a plurality of known arrangements and certain new arrange ments as will be described with reference to the accompanying drawings, given by way of example only.

Fig. 1 is an elevation of the brake.

Fig. 2 is a top plan view'thereof.

Fig. 3 is an elevation of the same brake seen from the opposite side to the view of Fig. 1.

Fig. 4 is a section thereof made according to the broken line "IV- l of Fig. l.

Fig. 5 shows a detail seen from the inner side of the brake, with partial sections.

Fig. 6 is a similar View, one of the small side plates of the support for the levers being broken away.

Two brake shoes a, a1, substantially semi-circular, and having a T-shaped profile, are urged, by two coil springs b, 121, to press, by their V- shaped ends, on the one hand, on a fixed pivot pin 2 and, on the other hand, on control levers d, all; this pin 0 and the pivot pins 6, 61 of levers d, 031 are fitted on a fixed plate 1 through the medium of respective supports g and h.

The support g comprises a member or flange l secured on the plate by two screws 2 passing through another flange 3-; this member is periorated with a tapped hole in which the pin 0 is screwed and held stationary by a lock-nut 4 externally arranged; moreover, it is provided with a flange 5 on which a ring 6 is centered. One of the ends of the pin 0 is so cut as to have sides l and that it can be easily turned by means of a Wrench, and its opposite end forms a conical head 8 serving to hold the shoes (1., on more or less spaced apart when they are at rest, in order to compensate the wear of their friction linings 9.

The ring 6 carries a tenon IE! on which bears the middle portion of the spring 19, the ends of which are attached to the shoes (1, in, so that this spring is bent in V shape and exerts on these latter oblique stresses tending to hold them pressed against the ring 6 at the same time as on the conical surface of the head 8.

The ring 6 is preferably made of a metal the coefficient of expansion of which is such that its variation of axial thickness and, consequently, the variation of diameter of the portion of the conical surface 8 on which the jaws bear, according as the brake drum [5 and, consequently,

the ring 6 itself are more or less heated up, ensure a suitable compensation of the pressure exerted by these shoes against the drum t in function of the temperature of the latter.

The holes ll provided in the plate for the passage of the screws 2 have a diameter larger than that of the screws, so that the position of the support g and of the pin c can be easily adjusted for centering to best advantage the shoes a, a1 within the drum.

The support it for the control levers consists in two bent sheet metal members l2 riveted on the plate 1 and braced by the pins e, m and by a median member it which serves, on the one hand, to carry a tenon l4 similar to the tenon ill and, on the other hand, to receive the tightening screw l5 of an outer plate l6 adapted to press a felt lining ll against the edges of the openings E8 of the plate 1 for preventing mud and dust from penetrating about the levers d, d1 which pass with play through these openings.

The brake is actuated by means of a Bowden transmission, the cable 2 of which is attached to a fork-piece y pivoted on the lever d and the sheath It of which presses against a fork piece l fitted on the lever air. The levers are normally pressed against abutments l9 owing to the fact that the shoes a, m are urged to move towards each other by the springs b b1 and act on the inner ends of the levers ct, (11, which ends are suitably cut away for receiving them. Moreover, in the present form of construction, the lever d1 is urged in the same direction by a coil spring m attached to an eye member Bil of this lever and to the pivot pin 6 of the opposed lever d, so as to balance the constant thrust of the sheath is which usually forms several bends.

The tensile stress produced by the rigging is transmitted by the cable 2 to lever d at 9", and, by reaction, the sheath it exerts an equal thrust on lever (11 at 2".

Each of the levers transmits this stress amplified in the ratio for lever 01, on the shoe a and for lever d1, on the shoe on.

These shoes are thus spaced apart by pivoting on the conical portion 8 of the pin 0 and move in contact with the drum t with equal or different stresses according to the purpose for which the brakes are used. In the embodiment illustrated, the stress exerted on the shoe w is smaller than that exerted on the shoe on, so that in the preferred direction of rotation R of the drum 1? and for a given friction coefiicient of the linings 9, the winding effects of the shoe a and the unwinding efiects of the shoe in produced for the friction torques, allow a strain and wear of the linings substantially equal for both shoes.

The spring 271 is curved on the tenon I4 as the spring b on tenon Ill and also urges the shoes a, on towards the plate I; the movable ends of said shoes are thus pressed against the edges 2| of the notches of the levers and their median portion takes a bearing against seats 22 secured on the plate 1 by riveting or otherwise. Owing to the fact that each shoe is guided at three points of its length forming a triangle, any rattling and lateral vibrations are completely avoided.

The notches 2|, Zla of levers (2, d1 guide the ends of the shoes and render unnecessary the use of guide links or similar members.

It is to be noted that the mode of attachment of the shoes and springs allows the brake to be fitted up and taken to pieces in a few seconds with the greatest ease. The number of parts to be removed when the linings are to be replaced or when the brake is to be inspected is reduced to the minimum, since it sufiices to remove the shoes and springs 11, 171. No special tool is necessary.

The construction allows of centering the shoes and of adjusting their action with the greatest ease.

The entire brake is light as well as of rugged construction and its cost price is low.

It is to be understood that the invention is not limited to the details of construction indicated above and that the arrangements described can be replaced by any equivalent arrangements without departing thereby from the scope of the present invention.

I claim- 1. In an internally acting brake, the combination of a fixed brake plate, carrying at a point near its periphery a fixed pivot pin at right angles to the plane of said plate, two brake shoes rigidly pivoted on this fixed pivot pin and so arranged as to act on the inner wall of a rotary drum, the free ends of said brake shoes being located at a point diametrally opposed to said fixed pivot pin, two operating levers pivoted on two pins rigid with said plate and parallel to the plane of this plate, these levers being unequal in length and so arranged that one of their ends is located outside the brake and their other end within said brake, and in such a manner as to act on the respective end of said brake shoes, coil springs oblique relatively to the plane of the plate, secured, on the one hand, to said brake shoes and, on the other hand, at a point of said fixed plate and so arranged as to press each of said brake-shoes, on the one hand, on said fixed pivot pin, at one of its ends, on the other hand, on the corresponding lever, at the other end, and on a seat rigid with said brake plate at an intermediate point.

2. A brake as claimed in claim 1, in which said oblique springs are constituted by coil springs each of which has its ends secured to said brake shoes and its middle point attached to a point of the brake plate located nearer to this plate than said ends, each spring thus having a V- shape.

3. A brake as claimed in claim 1, in which the unequal length of each of said operating levers is adjustable on the brake plate, so that it is possible to thus adjust the position of rest of each of said brake shoes and the distribution of the braking stresses on both brake shoes.

LUCIEN BERTRAND. 

